Batteries can be used for a variety of applications such as portable electronics (cell phones, personal digital assistants, music players, video cameras, and the like), power tools, power supplies for military use (communications, lighting, imaging and the like), power supplies for aerospace applications (power for satellites), and power supplies for vehicle applications (hybrid electric vehicles, plug-in hybrid electric vehicles, and fully electric vehicles). The design of such batteries is also applicable to cases in which the battery is not the only power supply in the system, and additional power is provided by a fuel cell, other battery, IC engine or other combustion device, capacitor, solar cell, etc.
Solid state cells are generally in the experimental state, have been difficult to make, and have not been successfully produced in large scale. Although promising, solid state cells have not been achieved due to limitations in cell structures and manufacturing techniques.
Solid state batteries have been proven to have several advantages over conventional batteries using liquid electrolyte in lab settings. Safety is the foremost one. Solid state battery is intrinsically more stable than liquid electrolyte cells since it does not contain a liquid that can cause an undesirable reaction, resulting thermal runaway, and an explosion in the worst case. Solid state battery can store more energy for the same volume or same mass than conventional batteries.
Despite of these outstanding properties of solid state batteries, there are challenges to address in the future to make this type of batteries available in the market. To exploit the compactness and high energy density, packaging of such batteries should be improved. To be used in variety of applications such as consumer electronics, RFID, etc., large area and fast film deposition techniques at low cost should be developed.